This invention provides for a mower elevational control system wherein the mowers can be raised to an intermediate elevation above the ground and thereby permit the tractor to be steered or turned around, but without mowing while turning. For instance, in the mowing of a golf course fairway, when the fairway is being mowed crosswise, the mowers are to be lifted when the machine meets the side edge of the fairway, so that the adjacent rough grounds will not be mowed. That is, the mowers are lifted along the sidelines of the fairway, and they are held in the lifted or predetermined elevated position until the tractor is turned 180 degrees and again approaches the fairway whereupon the mowers are lowered at that previously identified line and the fairway is then mowed in the opposite crosswise direction. In all instances, the rough is not mowed, and the operator need not attend to the function of maintaining the mowers raised while also operating the tractor, because the mowers are automatically retained in the raised position by the system of this invention, and the raised position and the subsequent lowered position are automatically achieved elevation-wise.
This invention provides a system whereby the mowers can be raised and lowered under controlled conditions. The prior art is aware of raising and lowering mowers, such as by hydraulic systems which this invention utilizes, but in the prior art, the operator was required to hold the hydraulic lift valve in the raised position until he could determine that the mowers were sufficiently raised to clear the grass which was not to be mowed, such as the aforementioned rough. Subsequently, in the prior art, the operator then had to hold or maneuver the hydraulic valve to the lowering position until the system completely lowered the mowers back to the ground. This is an operator-dependent system which is fatigueing and imprecise with regard to the amount of elevation, for instance. The prior art is also aware of a hydraulic system for raising mowers and wherein the control lever maneuvered by the operator can be actuated to raise the mowers and then the operator can release the lever and the mowers will remain raised until the operator again activates the lever for lowering the mowers. However, that type of system did not provide for the predetermined intermediate elevation between ground level and transport elevation of the mower, nor did it provide for the selective raising and lowering of certain ones of the mowers to a predetermined elevation, such as in this invention. Examples of the prior art utilizing hydraulic systems for raising and lowering mowers are shown in U.S. Pat. Nos. 3,511,035 and 3,808,778 and 3,992,858 and 4,878,338, and 3,177,638.
The present invention differs from the prior art in that it provides for a mower raising and lowering system wherein the mowers can be automatically positioned to a predetermined level, without requiring the continuous attention of the operator, and the mowers can then be retained in that predetermined elevation, again, without requiring the attention of the operator, and subsequently the mowers can be lowered to the ground, again, without the continuous attention of the operator.
Still further, the present invention provides for a mower-lifting and lowering system wherein certain of the mowers, such as the wing mowers can be raised independent of the other mowers of a gang of mowers supported on a tractor, and the wing mowers can be raised to a transport position independent of raising the other mowers of the gang, all while accomplishing the aforementioned objective of alternately being able to raise all of the mowers to the predetermined elevation for the fairway mowing example described.
In accomplishing the aforementioned objectives, the present system requires only that the operator initiate the raising or lowering action and then the system described herein controls the raising and lowering action to the desired predetermined elevation and back down to the ground, all without requiring the operator's further attention after the operator has initiated either the raising or the lowering action. As such, this greatly reduces operator fatigue and it does not require operator skill and attention throughout the entire process of raising, retaining, and subsequently lowering the mowers to the ground.